FOTAKIS, D. A.; NIKOLETSEAS, S. E.; PAPADOPOULOU, V. G.; SPIRAKIS, P. G. HARDNESS RESULTS AND EFFICIENT APPROXIMATIONS FOR FREQUENCY ASSIGNMENT PROBLEMS: RADIO LABELLING AND RADIO COLORING. Computing and Informatics, [S. l.], v. 20, n. 2, p. 121–180, 2012. Disponível em: https://www.cai.sk/ojs/index.php/cai/article/view/514. Acesso em: 1 may. 2025.